1. Field of the Invention
The present invention relates to a fuel cell system.
2. Description of the Related Art
Recently, flourishing is a development of a polymer electrolyte fuel cell (PEFC: hereinafter referred to as “fuel cell”) where hydrogen is supplied to an anode and oxygen to a cathode, thereby an electrochemical reaction occurs and power is generated. The fuel cell is being applied in a wide range to such a fuel cell vehicle run by power generated the cell and a home power source, and also hereafter, its application range is expected to expand.
If generating power, such the fuel cell generates heat by itself according to an electrochemical reaction. Consequently is generally adopted a method of circulating a refrigerant (cooling water) via the fuel cell and appropriately cooling the cell (see paragraphs 0022 to 0025 and FIG. 1 in Japanese Patent Laid-Open Publication No. 2004-234902).
On the other hand, in order to downsize the system, a technology is proposed that integrally configures a pump for supplying a refrigerant and a compressor for supplying air to a cathode and that integrally drives them with one drive device (for example, a motor).
However, thus if a pump and a compressor have one drive device in common and are integrally driven, for example, air and a refrigerant are sent in activating a fuel cell, and heat generated by self heat generation is radiated into the refrigerant; as a result, warming up the fuel cell is delayed in some case. Furthermore, in a case of activating a fuel cell below a freezing point, there is also a possibility that water generated by power generation and condensed water freeze within the cell, depending on a refrigerant.
Consequently, there is a need for a fuel cell system that can be downsized and preferably warmed up.